Method for producing low-sulfur and low-phosphorus steel by utilizing semi-molten steel

Abstract

The invention relates to a method for producing low-sulfur and low-phosphorus steel by utilizing semi-molten steel. The method comprises the following steps: acquiring low-sulfur and low-phosphorus molten steel by the semi-molten steel through pre-deoxidation, KR desulfurization, converter steelmaking, LF refining and VD vacuum smelting in sequence, and acquiring the low-sulfur and low-phosphorussteel by pouring the low-sulfur and low-phosphorus molten steel, wherein the sulfur content of the molten steel subjected to KR desulfurization is lower than or equal to 0.005%, the rate of slagging-off after KR desulfurization is higher than or equal to 90%, the phosphorus content of the molten steel subjected to converter steelmaking is lower than or equal to 0.004%, 10-30 kg of slagging balls are added into the molten steel per ton during converter steelmaking, the included angle of oxygen gun holes during converter steelmaking is larger than or equal to 13 degrees, and the final temperature of converter steelmaking is lower than or equal to 1620 DEG C. According to the method provided by the invention, the off-site sulfur content is lower than or equal to 0.005% and the rate of dephosphorization during the converter steelmaking of the semi-molten steel reaches 96% or higher. Meanwhile, hydrogen-sulfide-corrosion-resistant continuous-casting round billet non-metallic inclusions produced through the method reach the following levels: class A is lower than or equal to level 0.5; class C is equal to level 0; class B and class C are lower than or equal to level 1.0; and the total thickness of class A, class B, class C and class D is lower than or equal to level 3.0.

Description

technical field [0001] The invention relates to the field of steelmaking, in particular to a method for producing low-sulfur and low-phosphorus steel by utilizing semi-steel. Background technique [0002] At present, according to statistics, about 1 / 3 of the world's proven oil and gas fields contain H 2 S gas, containing H 2 The exploitation of S oil and gas fields is increasing day by day, thus making the anti-H 2 The consumption of S corroded line pipe has increased significantly. Anti-H 2 S corrosion line pipe is mainly used to transport 2 S oil and gas, its service environment is extremely harsh, and its corrosion resistance has extremely high requirements. If the line pipe is severely perforated or cracked during the transportation of oil and gas, it will lead to major safety accidents such as fuel leakage and explosion and social and economic losses. Therefore, the line pipe is required to have high strength, toughness, good welding performance and better Corrosi...

AI Technical Summary

Problems solved by technology

[0002] At present, according to statistics, about 1 / 3 of the world's proven oil and gas fields contain H 2 S gas, containing H 2 The exploitation of S oil and gas fields is increasing day by day, thus making the anti-H 2 Substantial increase in consumption of S corrosion line pipe

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